The present invention pertains to equipment used in processing x-ray films and more particularly pertains to an x-ray cassette positioner and cogbelt for use therewith.
It is convenient to handle x-ray film within cassettes that protect the film from extraneous light and damage. This is particularly the case for storage phosphor films (also referred to as stimulable phosphor film) in which the film is read by photoelectrically detecting an image formed by scanning with stimulating radiation. An example of such a scanner-reader is disclosed in U.S. Pat. No. 4,789,782 to Ohara. It is desirable to retain the x-ray film within a cassette except during actual processing. Such an x-ray cassette is disclosed in a U.S. patent application cofiled with this application entitled "X-RAY CASSETTE HAVING REMOVABLE PHOTOGRAPHIC ELEMENT" by Jeffrey C. Robertson, which is incorporated herein by reference. A hooked extractor can be used with that x-ray cassette to move a photographic element to and from an x-ray reader for processing. It is desirable to provide an apparatus to automate the presentation of such x-ray cassettes or similar cassettes to such an extractor so that a number of x-ray cassettes could be processed in succession without attention from an operator. It is also desirable that such an apparatus be able to accurately position x-ray cassettes sequentially to simplify removal and reinsertion of the photographic elements and that the presentation apparatus be separate from the x-ray reader to permit interchange of units and reduce repair times.
X-ray cassettes can be relatively heavy and present a risk of mishap when carried unless the x-ray cassettes can be held with both hands in a horizontal position. It is desirable that a device for positioning x-ray cassettes to an extractor permit an x-ray cassette to be held horizontally with both hands during loading and unloading and thus, for simplicity, that the device transport x-ray cassettes in a horizontal orientation. U.S. Pat. No. 4,915,578 to Becker teaches a device, from another art, which transports horizontally oriented bins. The bins are moved by means of a pair of chain conveyors mechanically driven in unison. The device is loaded from the top with a stack of nested bins which are then dropped out the bottom one at a time onto a conveyor. It is desirable that an x-ray cassette positioner receive the cassettes one at a time and not dispense the x-ray cassettes, but rather hold them for manual unloading. Since exposed x-ray cassettes are not generic items, it is also desirable that it be possible to rearrange the order of the x-ray cassettes within the positioner, as requirements change.
X-ray cassettes typically come in a number of standard sizes, for example 11 by 14 inches, 10 by 12 inches, and 8 by 10 inches. It is also desirable that means be provided for accepting a plurality of different size cassettes with out any need to adjust or modify the apparatus.